Apparatus of the multiplunger type are used for enclosing semiconductor elements with resin to produce semiconductor devices. Such apparatus are disclosed, for example, in U.S. Pat. Nos. 4,347,211, 4,388,265 and 4,511,317 and U.S. patent application Ser. No. 796,814. Among these apparatus, the apparatus of U.S. Pat. No. 4,388,265 has the following construction.
The apparatus has a stationary die, a movable die opposed to the stationary die, a plurality of pots formed in one of the dies, a plurality of cavities provided between the two dies, gates for holding each of the pots in communication with specified cavities around the pot, plungers arranged in corresponding relation with the pots in position and in number, a mechanism for reciprocatingly moving the plungers, etc.
Such conventional apparatus are primarily designed for the mass production of semiconductor devices having a high quality. Accordingly, the cavities in the cavity blocks are usually shaped identically. Further for the purpose of mass production, each cavity block is usually fixed to a die base. Thus, the apparatus is not so adapted that one of various cavity blocks is selectively removably mountable on the die base.
In recent years, however, a wide variety of semiconductor devices are often produced in small quantities. In such a case, it is critical that desired cavity blocks be readily interchangeable for use on the die base.
With the conventional apparatus of the type described, nevertheless, no consideration is given to easy and frequent changeability of cavity blocks for the die base. Whereas the plungers, plunger holder, and ejector plate must invariably be changed with the replacement of the cavity block, no consideration whatever is therefore given to easy changeability of these components.
Thus, the conventional semiconductor element enclosing apparatus is not so adapted that the cavity block and other members are easily changeable. Since these components are extremely difficult to change, the apparatus has the inherent problem of reduced production efficiency when it is used for producing various semiconductor devices in small quantities.